Over time, by trial and error, they found out
study of the mystical side of life.
Some alchemists are said to have tried to convert common metals into gold, and to find a potion that would give people eternal life. While doing this they made many useful discoveries about natural materials.
The ancient Greek philosophers were also interested in how the world was put together.
Democritus (~ 400 BC) proposed that matter was made of invisible particles that he called atoms.
He had no way of testing his theory, and other more popular philosophers disagreed with him.
During the Renaissance, scholars began to make a systematic study of matter. People like Lavoisier are credited with developing the "Scientific Method" of observing, hypothesising and designing and doing experiments to test the hypotheses.
Gradually, our knowledge of chemistry built up. Today we have a vast number of human-made materials, and can design chemicals to do just about any job we want. eg materials to use in joint replacements.
Pages by Sally Mack 1998-2001